Estrogen therapy increases BMD in transgender women

Issue: July 2016

In transgender women, estrogen therapy was shown to increase bone mineral density in both the lumbar spine and total hip during the first year of treatment, according to study findings presented at the European Congress of Endocrinology.

In a prospective, observational study, Chantal Wiepjes, MSc, a PhD student in the department of internal medicine and the Center of Expertise on Gender Dysphoria at VU Medical Center in Amsterdam, and colleagues analyzed data from 188 adults who completed cross-sex hormone therapy (99 female-to-male transgender men). All patients underwent DXA scans of the lumbar spine and total hip at baseline and 1 year. Transgender men received Aveed (intramuscular testosterone undecanoate, Endo Pharmaceuticals; 1,000 mg every 12 weeks), testosterone gel (50 mg daily) or testosterone esters intramuscular (250 mg biweekly). Transgender women were prescribed cyproterone acetate (50 mg daily) combined with oral estradiol (2-4 mg daily) or an estradiol patch (200 µg weekly). Researchers stratified analyses for calcium with colecalciferol use.

At 1 year, transgender women saw a greater increase in lumbar spine BMD vs. transgender men (3.72% vs. 1%) and a greater increase in total hip BMD (1.52% vs. 0.91%). BMD increases were greater in transgender women taking calcium with colecalciferol vs. those not taking calcium at the lumbar spine (4.87% vs. 2.86%) and total hip (2.33% vs. 0.92%); calcium use did not influence BMD changes in transgender men.

“As this increase was only found in those with low pretreatment estrogen levels, it might suggest that in biological adult women (premenopause), testosterone primarily affects bone density through its conversion into estrogen,” Wiepjes said in a press release.

Wiepjes said next steps will include investigating the long-term effects of hormone treatment on bone density.

“Patients undergoing hormone therapy routinely have bone density scans, which might give them the impression that hormone treatment can have adverse effects on their bones,” Wiepjes said. “Therefore, a more solid molecular long-term understanding of the changes may reassure them.” – by Regina Schaffer

Reference:

Wiepjes C, et al. Abstract OC11.1. Presented at: European Congress of Endocrinology; May 28-31, 2016; Munich.

Disclosure: Endocrine Today was unable to determine any relevant financial disclosures.